feat(devices): update the device last seen timestamp on usage

src/api/client_server/device.rs

@@ -17,8 +17,8 @@ pub async fn get_devices_route(
 
     let devices: Vec<device::Device> = services()
         .users
-        .all_devices_metadata(sender_user)
-        .filter_map(|r| r.ok()) // Filter out buggy devices
+        .all_user_devices_metadata(sender_user)
+        .await
         .collect();
 
     Ok(get_devices::v3::Response { devices })

src/api/client_server/sync.rs

@@ -71,6 +71,17 @@ pub async fn sync_events_route(
 ) -> Result<sync_events::v3::Response, RumaResponse<UiaaResponse>> {
     let sender_user = body.sender_user.expect("user is authenticated");
     let sender_device = body.sender_device.expect("user is authenticated");
+
+    let cloned_sender_user = sender_user.clone();
+    let cloned_sender_device = sender_device.clone();
+    // No need to block sync on device last-seen update
+    tokio::spawn(async move {
+        services()
+            .users
+            .update_device_last_seen(cloned_sender_user, cloned_sender_device)
+            .await;
+    });
+
     let body = body.body;
 
     let mut rx = match services()
@@ -1274,6 +1285,17 @@ pub async fn sync_events_v5_route(
 ) -> Result<sync_events::v5::Response, RumaResponse<UiaaResponse>> {
     let sender_user = body.sender_user.expect("user is authenticated");
     let sender_device = body.sender_device.expect("user is authenticated");
+
+    let cloned_sender_user = sender_user.clone();
+    let cloned_sender_device = sender_device.clone();
+    // No need to block sync on device last-seen update
+    tokio::spawn(async move {
+        services()
+            .users
+            .update_device_last_seen(cloned_sender_user, cloned_sender_device)
+            .await;
+    });
+
     let mut body = body.body;
     // Setup watchers, so if there's no response, we can wait for them
     let watcher = services().globals.watch(&sender_user, &sender_device);

src/api/ruma_wrapper/axum.rs

@@ -89,7 +89,7 @@ where
             if let Some(reg_info) = services().appservice.find_from_token(token).await {
                 Token::Appservice(Box::new(reg_info.clone()))
             } else if let Some((user_id, device_id)) = services().users.find_from_token(token)? {
-                Token::User((user_id, OwnedDeviceId::from(device_id)))
+                Token::User((user_id, device_id))
             } else {
                 Token::Invalid
             }

src/api/server_server.rs

@@ -2351,8 +2351,8 @@ pub async fn get_devices_route(
             .expect("version will not grow that large"),
         devices: services()
             .users
-            .all_devices_metadata(&body.user_id)
-            .filter_map(|r| r.ok())
+            .all_user_devices_metadata(&body.user_id)
+            .await
             .filter_map(|metadata| {
                 Some(UserDevice {
                     keys: services()

src/database/key_value/users.rs

@@ -41,7 +41,7 @@ impl service::users::Data for KeyValueDatabase {
     }
 
     /// Find out which user an access token belongs to.
-    fn find_from_token(&self, token: &str) -> Result<Option<(OwnedUserId, String)>> {
+    fn find_from_token(&self, token: &str) -> Result<Option<(OwnedUserId, OwnedDeviceId)>> {
         self.token_userdeviceid
             .get(token.as_bytes())?
             .map_or(Ok(None), |bytes| {
@@ -60,9 +60,11 @@ impl service::users::Data for KeyValueDatabase {
                     .map_err(|_| {
                         Error::bad_database("User ID in token_userdeviceid is invalid.")
                     })?,
-                    utils::string_from_bytes(device_bytes).map_err(|_| {
-                        Error::bad_database("Device ID in token_userdeviceid is invalid.")
-                    })?,
+                    utils::string_from_bytes(device_bytes)
+                        .map_err(|_| {
+                            Error::bad_database("Device ID in token_userdeviceid is invalid.")
+                        })?
+                        .into(),
                 )))
             })
     }
@@ -894,7 +896,7 @@ impl service::users::Data for KeyValueDatabase {
             })
     }
 
-    fn all_devices_metadata<'a>(
+    fn all_user_devices_metadata<'a>(
         &'a self,
         user_id: &UserId,
     ) -> Box<dyn Iterator<Item = Result<Device>> + 'a> {
@@ -912,6 +914,38 @@ impl service::users::Data for KeyValueDatabase {
         )
     }
 
+    fn set_devices_last_seen<'a>(
+        &'a self,
+        devices: &'a BTreeMap<(OwnedUserId, OwnedDeviceId), MilliSecondsSinceUnixEpoch>,
+    ) -> Box<dyn Iterator<Item = Result<()>> + 'a> {
+        Box::new(devices.iter().map(|((user, device), timestamp)| {
+            let mut key = user.as_bytes().to_vec();
+            key.push(0xff);
+            key.extend_from_slice(device.as_bytes());
+
+            // Device may have been removed since last db write
+            if let Some(mut device_metadata) = self
+                .userdeviceid_metadata
+                .get(&key)?
+                .map(|bytes| {
+                    serde_json::from_slice::<Device>(&bytes).map_err(|_| {
+                        Error::bad_database("Device in userdeviceid_metadata is invalid.")
+                    })
+                })
+                .transpose()?
+            {
+                device_metadata.last_seen_ts = Some(*timestamp);
+
+                self.userdeviceid_metadata.insert(
+                    &key,
+                    &serde_json::to_vec(&device_metadata).expect("Device always serializes"),
+                )?;
+            }
+
+            Ok(())
+        }))
+    }
+
     /// Creates a new sync filter. Returns the filter id.
     fn create_filter(&self, user_id: &UserId, filter: &FilterDefinition) -> Result<String> {
         let filter_id = utils::random_string(4);

src/database/mod.rs

@@ -1139,6 +1139,7 @@ impl KeyValueDatabase {
         services().sending.start_handler();
 
         services().media.start_time_retention_checker();
+        services().users.start_device_last_seen_update_task();
 
         Self::start_cleanup_task().await;
         if services().globals.allow_check_for_updates() {

src/main.rs

@@ -543,7 +543,7 @@ async fn shutdown_signal(handle: ServerHandle) {
     warn!("Received {}, shutting down...", sig);
     handle.graceful_shutdown(Some(Duration::from_secs(30)));
 
-    services().globals.shutdown();
+    services().globals.shutdown().await;
 
     #[cfg(feature = "systemd")]
     let _ = sd_notify::notify(true, &[sd_notify::NotifyState::Stopping]);

src/service/globals/mod.rs

@@ -512,11 +512,13 @@ impl Service {
         Ok(r)
     }
 
-    pub fn shutdown(&self) {
+    pub async fn shutdown(&self) {
         self.shutdown.store(true, atomic::Ordering::Relaxed);
         // On shutdown
         info!(target: "shutdown-sync", "Received shutdown notification, notifying sync helpers...");
         services().globals.rotate.fire();
+        // Force write before shutdown
+        services().users.try_update_device_last_seen().await;
     }
 }
 

src/service/mod.rs

@@ -29,7 +29,7 @@ pub struct Services {
     pub rooms: rooms::Service,
     pub transaction_ids: transaction_ids::Service,
     pub uiaa: uiaa::Service,
-    pub users: users::Service,
+    pub users: Arc<users::Service>,
     pub account_data: account_data::Service,
     pub admin: Arc<admin::Service>,
     pub globals: globals::Service,
@@ -112,10 +112,11 @@ impl Services {
             },
             transaction_ids: transaction_ids::Service { db },
             uiaa: uiaa::Service { db },
-            users: users::Service {
+            users: Arc::new(users::Service {
                 db,
                 connections: StdMutex::new(BTreeMap::new()),
-            },
+                device_last_seen: Mutex::new(BTreeMap::new()),
+            }),
             account_data: account_data::Service { db },
             admin: admin::Service::build(),
             key_backups: key_backups::Service { db },

src/service/users/data.rs

@@ -4,8 +4,8 @@ use ruma::{
     encryption::{CrossSigningKey, DeviceKeys, OneTimeKey},
     events::AnyToDeviceEvent,
     serde::Raw,
-    DeviceId, OneTimeKeyAlgorithm, OwnedDeviceId, OwnedMxcUri, OwnedOneTimeKeyId, OwnedUserId,
-    UInt, UserId,
+    DeviceId, MilliSecondsSinceUnixEpoch, OneTimeKeyAlgorithm, OwnedDeviceId, OwnedMxcUri,
+    OwnedOneTimeKeyId, OwnedUserId, UInt, UserId,
 };
 use std::collections::BTreeMap;
 
@@ -20,7 +20,7 @@ pub trait Data: Send + Sync {
     fn count(&self) -> Result<usize>;
 
     /// Find out which user an access token belongs to.
-    fn find_from_token(&self, token: &str) -> Result<Option<(OwnedUserId, String)>>;
+    fn find_from_token(&self, token: &str) -> Result<Option<(OwnedUserId, OwnedDeviceId)>>;
 
     /// Returns an iterator over all users on this homeserver.
     fn iter<'a>(&'a self) -> Box<dyn Iterator<Item = Result<OwnedUserId>> + 'a>;
@@ -202,11 +202,16 @@ pub trait Data: Send + Sync {
 
     fn get_devicelist_version(&self, user_id: &UserId) -> Result<Option<u64>>;
 
-    fn all_devices_metadata<'a>(
+    fn all_user_devices_metadata<'a>(
         &'a self,
         user_id: &UserId,
     ) -> Box<dyn Iterator<Item = Result<Device>> + 'a>;
 
+    fn set_devices_last_seen<'a>(
+        &'a self,
+        devices: &'a BTreeMap<(OwnedUserId, OwnedDeviceId), MilliSecondsSinceUnixEpoch>,
+    ) -> Box<dyn Iterator<Item = Result<()>> + 'a>;
+
     /// Creates a new sync filter. Returns the filter id.
     fn create_filter(&self, user_id: &UserId, filter: &FilterDefinition) -> Result<String>;
 

src/service/users/mod.rs

@@ -2,7 +2,8 @@ mod data;
 use std::{
     collections::{BTreeMap, BTreeSet},
     mem,
-    sync::{Arc, Mutex},
+    sync::{Arc, Mutex as StdMutex},
+    time::Duration,
 };
 
 pub use data::Data;
@@ -15,9 +16,11 @@ use ruma::{
     encryption::{CrossSigningKey, DeviceKeys, OneTimeKey},
     events::AnyToDeviceEvent,
     serde::Raw,
-    DeviceId, OneTimeKeyAlgorithm, OwnedDeviceId, OwnedMxcUri, OwnedOneTimeKeyId, OwnedRoomId,
-    OwnedUserId, UInt, UserId,
+    DeviceId, MilliSecondsSinceUnixEpoch, OneTimeKeyAlgorithm, OwnedDeviceId, OwnedMxcUri,
+    OwnedOneTimeKeyId, OwnedRoomId, OwnedUserId, UInt, UserId,
 };
+use tokio::{sync::Mutex, time::interval};
+use tracing::{debug, warn};
 
 use crate::{services, Error, Result};
 
@@ -32,10 +35,59 @@ pub struct Service {
     pub db: &'static dyn Data,
     #[allow(clippy::type_complexity)]
     pub connections:
-        Mutex<BTreeMap<(OwnedUserId, OwnedDeviceId, String), Arc<Mutex<SlidingSyncCache>>>>,
+        StdMutex<BTreeMap<(OwnedUserId, OwnedDeviceId, String), Arc<StdMutex<SlidingSyncCache>>>>,
+    pub device_last_seen: Mutex<BTreeMap<(OwnedUserId, OwnedDeviceId), MilliSecondsSinceUnixEpoch>>,
 }
 
 impl Service {
+    pub fn start_device_last_seen_update_task(self: &Arc<Self>) {
+        let self2 = Arc::clone(self);
+        tokio::spawn(async move {
+            // Actually writes the new device times to the database every 55 minutes.
+            // The device times are always returned fresh from memory
+            // if they have been changed after the last write.
+            let timer_interval = Duration::from_secs(60 * 5);
+            let mut i = interval(timer_interval);
+            loop {
+                i.tick().await;
+                let _ = self2.try_update_device_last_seen().await;
+            }
+        });
+    }
+
+    pub async fn try_update_device_last_seen(&self) {
+        debug!("Writing cached device last-seens to database");
+        for error in self.write_cached_last_seen().await {
+            warn!("Error writing last seen timestamp of device to database: {error}");
+        }
+    }
+
+    /// Writes all the currently cached last seen timestamps of devices to the database,
+    /// clearing the cache in the process
+    async fn write_cached_last_seen(&self) -> Vec<Error> {
+        let mut guard = self.device_last_seen.lock().await;
+        if !guard.is_empty() {
+            // TODO: Replace with `replace` once/if `tokio::sync::Mutex` implements the equivalent
+            // method from `std`: https://doc.rust-lang.org/std/sync/struct.Mutex.html#method.replace
+            // i.e. instead of the `let mut guard` above:
+            //let map = self.device_last_seen.replace(BTreeMap::new()).await;
+            // We do a clone instead as we don't want start having a backlog of awaiting `lock`s
+            // for all these DB fetches and writes, which admittedly, might not even be a big deal.
+            let map = guard.clone();
+            guard.clear();
+            drop(guard);
+
+            let result = self
+                .db
+                .set_devices_last_seen(&map)
+                .filter_map(Result::err)
+                .collect();
+            result
+        } else {
+            Vec::new()
+        }
+    }
+
     /// Check if a user has an account on this homeserver.
     pub fn exists(&self, user_id: &UserId) -> Result<bool> {
         self.db.exists(user_id)
@@ -68,7 +120,7 @@ impl Service {
             cache
                 .entry((user_id, device_id, conn_id))
                 .or_insert_with(|| {
-                    Arc::new(Mutex::new(SlidingSyncCache {
+                    Arc::new(StdMutex::new(SlidingSyncCache {
                         lists: BTreeMap::new(),
                         subscriptions: BTreeMap::new(),
                         known_rooms: BTreeMap::new(),
@@ -161,7 +213,7 @@ impl Service {
             cache
                 .entry((user_id, device_id, conn_id))
                 .or_insert_with(|| {
-                    Arc::new(Mutex::new(SlidingSyncCache {
+                    Arc::new(StdMutex::new(SlidingSyncCache {
                         lists: BTreeMap::new(),
                         subscriptions: BTreeMap::new(),
                         known_rooms: BTreeMap::new(),
@@ -189,7 +241,7 @@ impl Service {
             cache
                 .entry((user_id, device_id, conn_id))
                 .or_insert_with(|| {
-                    Arc::new(Mutex::new(SlidingSyncCache {
+                    Arc::new(StdMutex::new(SlidingSyncCache {
                         lists: BTreeMap::new(),
                         subscriptions: BTreeMap::new(),
                         known_rooms: BTreeMap::new(),
@@ -245,7 +297,7 @@ impl Service {
     }
 
     /// Find out which user an access token belongs to.
-    pub fn find_from_token(&self, token: &str) -> Result<Option<(OwnedUserId, String)>> {
+    pub fn find_from_token(&self, token: &str) -> Result<Option<(OwnedUserId, OwnedDeviceId)>> {
         self.db.find_from_token(token)
     }
 
@@ -519,11 +571,25 @@ impl Service {
         self.db.get_devicelist_version(user_id)
     }
 
-    pub fn all_devices_metadata<'a>(
+    pub async fn all_user_devices_metadata<'a>(
         &'a self,
-        user_id: &UserId,
-    ) -> impl Iterator<Item = Result<Device>> + 'a {
-        self.db.all_devices_metadata(user_id)
+        user_id: &'a UserId,
+    ) -> impl Iterator<Item = Device> + 'a {
+        let all_devices: Vec<_> = self
+            .db
+            .all_user_devices_metadata(user_id)
+            .filter_map(Result::ok)
+            // RumaHandler trait complains if we don't collect
+            .collect();
+        let device_last_seen = self.device_last_seen.lock().await;
+
+        // Updates the timestamps with the cached ones
+        all_devices.into_iter().map(move |mut d| {
+            if let Some(ts) = device_last_seen.get(&(user_id.to_owned(), d.device_id.clone())) {
+                d.last_seen_ts = Some(*ts);
+            };
+            d
+        })
     }
 
     /// Deactivate account
@@ -564,6 +630,14 @@ impl Service {
     pub fn find_from_openid_token(&self, token: &str) -> Result<Option<OwnedUserId>> {
         self.db.find_from_openid_token(token)
     }
+
+    /// Sets the device_last_seen timestamp of a given device to now
+    pub async fn update_device_last_seen(&self, user_id: OwnedUserId, device_id: OwnedDeviceId) {
+        self.device_last_seen
+            .lock()
+            .await
+            .insert((user_id, device_id), MilliSecondsSinceUnixEpoch::now());
+    }
 }
 
 /// Ensure that a user only sees signatures from themselves and the target user